Referring to FIG. 1, a conventional pneumatic saw disclosed in U.S. Pat. No. 6,006,435 includes a cylinder 11, a piston 12, a metal member 13 and a buffer member 14. The piston 12 is movable relative to the cylinder 11, and has a rod portion 121, and a piston portion 122 that is received in the cylinder 11 and that is in air-tight contact with the cylinder 11. The metal member 13 and the buffer member 14 are disposed in the cylinder 11. The buffer member 14 is located at one side of the metal member 13 opposite to the piston portion 122 of the piston 12.
When the piston 12 is actuated by compressed air to move the piston portion 122 toward the buffer member 14, the buffer member 14 serves to absorb the shock generated by the piston portion 122, and the metal member 13 serves to prevent the buffer member 14 from excessive deformation so as to prolong the service life of the buffer member 14.
However, the metal member 13 needs to occupy a space in the cylinder 11 so as to limit a travel distance of the piston portion 122 of the piston 12, and to limit the size of the buffer member 14.